Method and means for handling sheets in piles



Nov. l, 1960 H. J. sEEL 2,958,527

METHOD AND MEANS FOR HANDLING SHEETS IN PILES l N VEN TOR.

1 @W14 //w Y l Arr/R srs Nov. 1, 1960 H, J, SEEL 2,958,527

Y METHOD AND MEANS FOR HANDLING SHEETS IN PILES Original Filed Nov. 20, 1953 4 Sheets-Sheet 2 IN VEN TOR.

HOWARD .1 wS55/ 'gi/wl@ l @My/6%@ ATTR/VEYS Nov. 1, 1960 H. x. SEEI. 2,958,527

METHOD AND MEANS FOR HANDLING SHEETS IN PILES Original Filed Nov. 20, 1955 4 Sheeecs-Sheei 31 INVENTOR. ff 50i/MRD J SEEL Y Bfqgq @www ,j *M/W ATTO NE YS Nov. 1, 1960 H. J. sEEL 2,958,527

METHOD AND MEANS FDR HANDLING SHEETS IN PILES Original Filed Nov. 20. 1953 4 Sheets-Sheet 4 JNVENTOR hgOYMM/QD J. SEEL Arr" /vsys lVIETHOD AND MEANS FOR HANDLING SHEETS IN PILES Howard J. Seel, Chagrin Falls, Ohio, assignor to Harris- Intertype Corporation, a corporation of Delaware Continuation of application Ser. No. 393,299, Nov. 20, 1953. This application Sept. 29, 1959, Ser. No. 843,168

46 Claims. (Cl. 271-62) This invention relates to improvement in a method and means for handling sheets in piles. In certain of its aspects it is applicable both to the feeding and the delivery of sheets.

This is a continuation of my copending application Serial No. 393,299, filed November 20, 1953, now forfeited.

One of the objects of the invention is the provision of a method and means for continuously feeding sheets to a printing machine or receiving them on a single delivery station.

Another object is the provision of a novel method of continuously feeding sheets which permits the use of a single pallet only.

Another object is the provision of a method for the purpose stated which permits the use of mill skids for supporting the piles of sheets to be fed, thereby eliminating the necessity of hand-loading special pile boards.

Another object is the provision of a method and means for facilitating the insertion of a pallet or other portable support member which is to function as a support for a depleting pile while a new pile is brought into position beneath the depleted pile.

A further object is the provision of means for providing an air film between the pallet or portable support and the depleting pile to facilitate insertion and/ or withdrawal of' the support.

Another object is the provision of a hollow pallet or portable support member with ports in its upper and lower surfaces through which air under pressure may be ejected.

Still `another object is the provision of a pallet having a wedge-shaped forward edge in order that when inserted under a depleted pile the forward edge of the pile will not be raised sufliciently to impair the functioning of forwardend feeding mechanism.

Other objects and features of novelty will appear as I proceed with the description of that embodiment of the invention which, for the purposes of the present application, I have illustrated in the accompanying drawings, in which Fig. l is a plan view of a hollow pallet which may be employed in carrying out the invention;

Fig. 2 is a side edge View of the same looking in the direction of arrows 2 of Fig. l;

Fig. 3 is a fragmental sectional View on a larger scale, the View being taken substantially on the line 3 3 of Fig. l and showing a valve in the upper plate of the pallet in normal closed position;

Fig. 4 is a similar sectional View taken substantially on the line 4-4 of Fig. l and showing upper and lower valves in open position;

Fig. 5 is a fragmental cross-sectional view on a scale similar to that of Figs. 3 and 4 wherein open ports are used instead of valved ports;

Fig. 6 is a fragmental perspective view of a skid loaded with a pile of sheets, means for raising the skid, and tracks for supporting the side edges of a pallet;

Fig. 7 is a diagrammatic side elevational view of a depleted pile between which and the supporting skid a pallet is being inserted;

Fig. 8 is a similar View with the pallet. in fully operative position;

Fig. 9 is a similar View with the side edges of the pallet carried by supporting tracks and the unloaded skid being lowered for removal;

Fig. l0 is a similar view with the old skid removed and a new loaded skid in position to be raised into contact with the pallet;

Fig. 11 is a similar View showing the new pile raised into engagement with the lower surface of the pallet, the tracks having been removed from pallet supporting position;

Fig. l2 is `a similar view in which the pallet is being withdrawn and the depleted pile is being deposited upon the new main pile;

Fig. 13 is a diagrammatic side view of a depleted pile from which the sheets are being fed by a front end feeder the operation of which is not aifected by the insertion of the pallet, because the height of the depleted pile at its front end is not changed materially;

Fig. 14 is a similar View with a new pile raised into engagement with the pallet and the latter being withdrawn to deposit the depleted pile upon the top of the new pile; and

Fig. l5 is a fragmental perspective view of a pile of sheets supported by a plurality of temporary support members. Y

Apparatus heretofore proposed for the continuous feeding of large paper sheets to a high-speed printing machine has generally included means defining :a iiat auxiliary pallet for supporting a remnant pile while a new pile, arranged upon a further auxiliary pallet supported by the main pile platform is disposed beneath it, feeding from the remnant pile continuing. The new pile and the pallet which is supporting the remnant pile are then brought into juxtaposition and the pallet is then supposed to be withdrawn from beneath the remaining sheets of the remnant pile to deposit the latter on the new pile.

Systems of this kind have the disadvantage that in practice the pallet is extremely diiiicult, if not impossible, to insert or withdraw. Also, because of the adhesion between the pallet and the pile of paper above it, the pallet, if it can be withdrawn, disarranges the sheets of the depleted pile thereby necessitating stoppage of the printing machine until this diticulty can be corrected.

Another disadvantage of such previous systems is that the means defining the auxiliary pallet must first be placed upon a main pile supporting platform and the entire pile of sheets repiled by hand upon the auxiliary pallet before the pile can be put into the feeder. This is burdensome, time-consuming and costly. Furthermore, it is obvious that at least two such pallets must be provided for each machine.

Another system previously suggested proposes a special type of pile board having parallel grooves to receive a series of slats or tangs which define a pallet. The grooves have been necessary heretofore to allow the insertion of the slats or tangs. This system also requires unloading the sheets from the mill skid and piling them by hand on the special pile board.

The present invention eliminates hand loading of pallets or pile boards, permits use of but one auxiliary pallet or means defining a pallet, and provides a method of and means for the easy insertion and/or withdrawal of a pallet used for temporary support of a remnant pile. These objectives are accomplished by inserting portable support means such as a pallet between the main pile support and the pile after the latter has been depleted to a desired extent, and by providing a iilm of air between the support means and the surface or surfaces adjacent thereto during insertion and/or withdrawal of the support means.

Referring to the drawings, there is shown somewhat in detail in Figs. 1 to 5 inclusive a novel portable support member, shown in the form of a pallet, which constitutes an important part of the present invention. It is indicated generally by the reference number i4. It has a `frame comprising side bars l5 and lr6 and two spaced rear bars 17 and 18. The frame is shown as comprising also three cross bars 19, 20 and 2l, although their number and their spacing may be varied as conditions may dictate. Other forms of internal light weight reinforcement may be utilized. In the illustrated case all `of these frame bars including the cross bars are of the same height, except that the side bars l5 and lo have upper surfaces inclined downwardly at their forward ends in front of cross bar 2l, as indicated in Pig. 2.

There is attached to the frame on its underside a flat plate 22 and on the upper side there is attached a plate 23 which is ilat throughout the greater part of its extent. At its forward end however it is inclined downwardly to produce a tapered front end portion 24 which meets the flat plate- 22 and is secured thereto with a fluid-tight joint. The forward edge of the pallet is sometimes referred to hereinafter as a wedge shaped edge.

All of the joints between the frame and the bottom and top plates are sealed, and the cross bars i9, Ztl and 21 have small passages 25 therethrough, so that an air chamber is formed throughout the interior of the hollow pallet in advance of the rear bar l?. Behind that bar the top and bottom plates 23 and 22 have cutouts 26, exposing portions of the rear bar 18 to form hand holds 18. In order to provide air pressure in said chamber a short tube 27 is set into the side bar I5 and is connected with a hose 28 which preferably has a measuring valve 29` by means of which the operator may regulate the degree of pressure in the pallet.

The pallet should be light in weight and yet strong and rigid. Preferably the frame bars previously referred to are hollow metal members of substantially square cross section. Each of the top and bottom plates 23, 22 may be formed as a composite 0f wood and metal. In other words each plate may have a core 3l of wood and inner and outer metal skin sheets 32 and 33 cemented or otherwise firmly attached to the core.

In the simplest form of the pallet there are provided at intervals throughout the extent of the bottom plate 22, small open ports 22', as illustrated in Fig. 5, while similar open ports 23i are formed in the upper plate 23.

Furthermore, I desire it to be understood that the use of a hollow portable support member, or pallet, while preferred, is not essential. In other words, tubular conductors could be installed in the portable support member at one or both surfaces thereof, connected with an air pressure supply and provided with ports through which air could be ejected.

Referring now to the form of pallet illustrated in Figs. 3 and 4, at intervals throughout the top plate 23 the core 31 and outer skin 33 are cut away to form circular cavities 34. A port 35 is cut through the inner skin 32 concentric with each cavity 34. Through each such port there extends a Valve stem 36 forming part of a valve indicated generally at 43. In an external groove in this stem there is mounted a lock ring 37 which supports a washer 38 upon which is carried a gasket 39 which is adapted to seat against the inner side of skin 32 for closing the valve port 3S. On its outer extremity the stem 36 has a circular abutment 4l) with a bevelled periphery, the abutment extending outwardly a short distance beyond the level of the skin 32 when the valve is closed as it is normally under the iniiuence of a compression spring 41 bearing against the outer side of skin 32 and the underside of the abutment. The stem is provided with a small bleed passage 42.

Valves indicated generally at 44 are mounted in the bottom plate 22 at points staggered with respect to the valves 43. The valves 44 are like the valves 43 except that they need not have the bleed passage 42. All of the valves in both plates are normally closed.

At the `front edge of the pallet there is a series of open ports. While these ports may be located in the joint between the meeting plates 22 and 23, I prefer to form them in both of those plates slightly to the rear of the joint, those in the top plate being indicated at d6 in Fig. l, and those in the bottom plate being preferably in line with the ports 46 in order that each pair may be formed by a single drilling operation.

Referring now to Fig. 6, Eli indicates a mill skid having parallel rails 51 and a board 52 supported thereby upon which a pile of sheets 53 is carried. The rails 51 are of sufficient height to support the board 52 a distance above the floor or other support upon which the skid rests. Consequently, lifting bars 54 may be slid into position beneath the board. The outer ends of these bars are notched to receive beams 55' to the ends of which are attached cables or chains 56 forming part of a conventional pile lifting and lowering mechanism of which other parts are not herein shown. Such mechanism includes means for lifting the pile of sheets step by step an increment at a time to maintain the top of the pile at a predetermined level so that sheets may be fed off the pile onto a feed board indicated at S7 with the sheet separating and feeding mechanism remaining at a xed level.

In apparatus of this kind, when the loaded skid has been raised to such a height that only a remnant of the pile remains on the skid, the operator inserts temporary, portable, pile supporting means between the skid and the depleting pile of sheets. ln the illustrated embodiment the portable supporting means comprises the pallet described which is somewhat wider and somewhat longer than the sheets of paper making up the pile, the dimensions o-f the maximum sheet being indicated by the broken line 58 of Fig. l. The operator grasps the pallet by the hand holds i8 and directs its front tapered edge between the skid and the bottom sheet of the depleted pile. At the same time he or his helper turns compressed air into the hose 28 and thus iills the chamber within the hollow pallet with compressed air. The small ports 46 at the forward edge of the pallet serve to eject compressed air between the skid and the pile, thereby facilitating the entering movement of the pallet. With a pallet having open ports such as illustrated in Fig. 5, air in tine streams is ejected from all such ports, and a film of air is provided above and below all portions of the pallet as the latter is advanced into operative position. When a pallet having valved ports 43 and 44 as illustrated in Figs. 3 and 4 is used, the upper and lower valves 43 and 44 in the tapered nose of the pallet encounter the bottom sheet of the pile and the upper surface of the pallet, those valves are opened by the pressure resulting from the weight of the pile and they release air to form a lm above and below the pallet which serves in the nature of lubricating means to make easy the inward movement of the pallet. Similarly, as the insertion of the pallet continues succeeding ines of Valves 43 and 44 open and facilitate the action.

The beginning of the insertion of the pallet is indicated diagrammatically in Fig. 7. The completion of the movement is shown in Fig. S. Sheet separating and forwarding mechanism comprising suckers 77 and the usual combers, strippers and other devices are employed at the rear of the pile. The thickness of the pallet is less than the range of sucker operation, or suitable adjustments of the pile may be made by the operator to maintain the separating mechanism in operation while the pallet is being inserted yor withdrawn or while it supports the remnant pile. The thickness of the pallet therefore does not adversely affect the operation of the feeder.

If the weight of the depleted pile should be insufcient to depress valve 43 against the action of its spring, the bleed passage 42 will still deliver air to the upper surface of the pallet to form the desiredair ilm. No such bleed passage is necessary inthe valves 44 because in that case the weight of the pallet is added to the weight of the depleted pile and the opening of those valves is assured.

Now the pallet being in place as indicated in Fig. 8, and being supported by the skid S0, which in turn is supported by the lifting bars 54 and the beams S5 hanging from the cables, the operator next turns off the compressed air and operates through controls to cause tracks 60, preferably formed of angle iron and carried upon depending arms 61, to move inwardly directly beneath the side edges of the pallet as indicated in Fig. 9. Now the pallet is supported independently of the skid. The empty skid 50 may now be lowered as indicated in Fig. 9 and withdrawn and a new loaded skid Sil' may be placed in position and connected with the lifting means as indicated in Fig. 10.

The feeding of sheets from the depleted pile continues after its transfer from the skid to the pallet. The top of the pile must be maintained at the proper level to enable the feeding mechanism to feed sheets onto the feed board 57, and this is done by elevating the tracks 60 and the pallet carried thereby step by step in any suitable or known manner.

With the parts in the position illustrated in Fig. 10, the operator by manipulating suitable controls causes the new skid S0 to rise until the pile carried thereby comes into juxtaposition with the bottom surface of pallet 14. Preferably the new pile is brought into contact with the bottom of the pallet so that the pallet is supported upon the new pile as shown in Fig. 11. He then operates controls to cause the tracks 60 to be backed away from the pallet. The step by step raising of the main pile is now resumed. The operator then turns on the compressed air, causing air to be ejected from both the upper and lower surfaces of the pallet throughout its extent, whereupon he may readily withdraw the pallet as indicated in Fig. 12, thereby depositing the remaining sheets of the depleted pileupon the top of the new pile. If necessary suitable stops may be used to hold such remaining sheets from following the pallet as it is being withdrawn, or the operator may perform this function by hand.

If desired the operator may being the new pile into such state of juxtaposition as to be merely close beneath but not supporting the pallet and thereafter withdraw the pallet along the tracks 60 to deposit the depleted pile upon the new pile, in which event of course the step by step raising of the pallet will cease and the step by step raising of the main pile will begin at about the time of of such deposit.

In Figs. 13 and 14 there is shown an example of the invention applied to a conventional front end feeder. In this feeder the sheet separating and forwarding mechanism is located along the front edge of the upper surface of the pile and may consist of suckers 70 which descend to pick up the sheet and move forward to place it in the bite of pull-in rolls 71, 72 which forward it along feed board 76, all in known manner. The usual uing air blasts, strippers and other devices not shown may be utilized in conjunction with suckers 70. In this type of feeder the distance between the suckers 70 or other feeding devices and the top of the pile must be maintained substantially constant in order that the feeder may function properly. The present invention lends itself well to this feeder anangement because when the pallet 14 is inserted between the pile board 52 of the skid and the depleted-pile carried thereby it lifts a major part of the` pile but does not appreciably change the height of the forward end of the pile upon which the feeding mechanism acts. Hence the feeding goes on satisfactorily. Also when anew pile is brought into positionA in engage- 6 ment with the underside of the palletand the feeding of sheets continues while the main pile is elevated step by step, the withdrawal of the pallet as indicated in Fig. 14 lowers the rear edge of the composite pile but has no effect on the forward end upon which the feeding mechanism is operating.

It is obvious that, while I have referred to inserting the pallet or portable support means between the bottom sheet of the depleted pile and the platform, the portable support means may be inserted at any desired point in the depleted pile such as between the main body of the depleted pile and one or a number of lowermost sheets thereof. In the latter case the lowermost sheet or sheets of the pile in effect become a part of the platform and provide a desirably smooth and continuous surface along which to move the portable support means during its insertion.

It will also be apparent that portable suppont means defining the pallet shown and described may be employed for temporarily supporting a thin pile of printed and delivered sheets while ya loaded skid. or pile board is removed and an empty skid or pile board put in place to receive a new pile of delivered sheets, after which the pallet is withdrawn and the sheets carried thereby deposited upon the skid or pile board.

While the pallet has been shown as being in one piece, it is considered to be within the scope of my invention to make the temporary support means sectional, i.e. as ya plurality of portable support members, and to insert and/or withdraw the sections separately.

Fig. l5 illustrates a plurality of portable support members 14a which have been inserted under a partially depleted pile, and which are used as a pallet or support for the pile under which they are inserted. The portable suppont members extend beyond the sides of the pile supported thereon and the louter end portions thereof rest on the cross bars of a hoist which may be the cross bars or tracks 60 of the hoist previously described for lifting the pallet 1'4. The parts of the hoist shown in Fig. l5 have, therefore, been given the same reference numerals as the previously described hoist. It can be readily perceived that the support members 14a define a sectional temporary support means which is the equivalent of the previously described pallet 14, but wherein the separate sections or support members 14a can be inserted or withdrawn from their pile supporting position separately of each other.

Having thus described my invention, I claim:

l. A method of disposing a pallet between a pile of sheets and its supporting surface, comprising the steps of inserting said pallet between the pile and its supporting surface, providing an air iilm between the pallet and the pile during insertion for facilitating the insertion, supporting the pile solely on the pallet, and transport-ing the pallet and pile thereon independently of the initial supporting surface.

2. The method of disposing a pallet between a pile of sheets and its supporting surface according to claim 1, which comprises the step of providing a lm of air between the pallet and the supporting surface below the pallet during insertion for facilitating the insertion.

3. A method of continually handling sheets, which comprises the steps of disposing a portable support member in position to provide support for a pile of sheets the thickness of which varies gradually during the operation of a sheet-handling machine with which the pile of sheets is associated, bringing a subjacent supporting surface into juxtaposition with the bottom of said support member, and withdrawing the support member as a support for the pile when the pile is to be deposited onto the subjacent supporting surface disposed therebeneath and facilitating the withdrawal of the support member by providing a film of air under pressure between the support member and the pile thereon during the withdrawal of the support member.

4. A method of continuously handling sheets which comprises the steps of depositing a portable support member including an air chamber in position to temporarily provide a support for a pile of sheets the thickness of which varies gradually during the operation of a sheet-handling machi-ne with which the pile of sheets iS associated, withdrawing the support member as a support when the pile is to be deposited on a surface therebeneath and simultaneously with the withdrawal introducing air under pressure into the interior of said chamber and ejecting the air from the support member to provide a film of air between the top surface of the support member and the pile for facilitating the withdrawal of the support member.

5. A method of continuously feeding sheets, disposing a pallet between a platform and a pile of sheets thereabove, feeding sheets one after another from the top, of the pile, supporting said pallet independently of the platform when the pile is diminished materially, removing said platform, placing a new pile in position under the depleted pile, bringing the top surface of the new pile into juxtaposition with the bottom of the pallet, introducing air between the top of the pallet and the depleting pile, and withdrawing the pallet to deposit the remaining portion of the depleted pile upon the new pile.y

6. A method of continuously feeding sheets as defined in claim including the additional step of ejecting the. air from within the pallet to provide the iilm of air between the top of the pallet and the bottom of the depleting pile.

7. A method of handling sheets in piles comprising the steps of inserting a pallet between a pile of sheets and its supporting surface, providing an air film from within the pallet between the pallet and the pile during the insertion for facilitating the insertion of the pallet, and supporting the entire pile on the pallet for subsequent handling independently of the supporting surface.

8. A method` of handling sheets in piles, comprising the steps of inserting a pallet between a pile of sheets and its supporting surface, ejecting air from within said pallet upwardly and downwardly during the insertion to provide air films above and below the pallet for facilitating the insertion of the pallet, and supporting the entire pile on the pallet for subsequent handling independently of the. supporting surface.

9. A method of continuously handling sheets, which comprises the steps of disposing a support member in position to temporarily provide a support for a pile of sheets the thickness of which varies gradually during operation of the sheet handling machine with which the pile of sheets is associated, providing a tilm of air under pressure between the support member and the pile for facilitating the withdrawal ofy the support member, and withdrawing the. support member to deposit the pile upon a subjacent supporting surface.

l0. A method of continuously handling sheets as defined' in claim 9 comprising the steps of bringing said subj'acent supporting surface and the support member into contact so that the support member and the said pile are supported by'sai'd subjacent supporting surface, and introducing a film of4 air under pressure between the support member and said subja'cent supporting surface for facilitating withdrawal ofthe supporti member.

ll. A method of continuously feeding sheets, com-prising supplying a pile of sheets on a main platform, feeding sheets one after another from the top of the pile until the height of the pile is diminished materially, inserting a portable support member between the platform andthe depleting pile and simultaneouslyl introducing air under pressure between at least one surface of the support member and ya surface adjacent thereto, removing the platform andV using the support member as a support for the depleting pile, and continuing the feeding of sheets from the depleting pile, placing a new pile in position under the depleting pile, bringing the support member and the new pile into juxtaposition, and withdrawing the support member to deposit the remaining por-tion of the depleting pile onto the new pile.

12. In the method of continuously feeding sheets wherein sheets are repeatedly taken one at a time from the top of a pile, thesteps of inserting a portable support means between the pile and the pile support therefor when the pile has been partially depleted, introducing air between the portable support means and the adjacent sheet of the pile during the insertion of the portable support means by supplying air from within the portable support means, and utilizing the portable support means independently of the said support as a second support for the pile while `a new pile is being brought into a position under the pile from which the sheets are being taken.

13. A method of continuously feeding sheets as defined in claim l1, comprising the step of introducing air under pressure between at least one surface of the member and the surface adjacent thereto during withdrawal of the member.

14. A method of continuously feeding sheets as defined in claim ll, comprising the step of discharging air from a wedge-shaped leading edge of said member as the member is inserted between the platform and the depleted pile.

l5. A method of continuously feeding sheets as defined in claim 13 wherein the air introduced between the support member and the adjacent surface comes from within the support member and the support member is provided with valved ports, and wherein the pressure of the depleting pile on the top surface of said support member is caused to open the valves in said ports progressively as the support member is pushed into position under the pile and to progressively close said valves as the support member is withdrawn.

16. A method of transferring a pile of sheets supported on a pallet to a subjacent supporting surface, comprising the steps of withdrawing the pallet from between the pile and its supporting surface, providing an air lm between the pallet and the pile during withdrawal for facilitating the withdrawal, and thereafter supporting the pile solely on the subjacent supporting surface.

17. A method of continuously feeding sheets, comprising supplying a pile of sheets on a platform, disposing a portable support member between said pile and said platform, feeding sheets one after another from the top of the pile until the height of the pile is diminished materially, supporting said support member independently of the platform, removing said platform and bringing a new pile of sheets on the platform into position below said pallet, and withdrawing the support member and simultaneously introducing from within the support member and at a plurality of areas spaced from each other air under pressure between the support member and pile to facilitate depositing the remaining portion of the depleted pile upon the new pile, and discontinuing the supply of air at said areas as they move out from under the pile during withdrawal of the support member.

18. A method `of continuously feeding sheets, comprising supplying a pile of sheets on a skid, feeding sheets one after another from the top of the pile and raising the skid gradually as the height of the pile diminishes, inserting a hollow pallet between the skid and the pileV when depleted While forcing air into the pallet, and through ports in its top and bottom surfaces to relieve friction between the pallet and the skid on the one hand and between the pallet and the depleted pile on the other hand, withdrawing the skid, continuing the feeding of sheets from the depleted pile while placing a new skid-supported pile in position under :the depleted pile gradually to maintain the top of the pile at a given level, raising the new skid-supported pile until it engages the bottom of the pallet, and withdrawing the pallet while forcing air through the said ports to reduce friction between thepallet and the bottom surface of the depleted pile and between the Q pallet and the top surface of the new pile, and resuming the gradual elevation of the new skid-supported pile with the depleted pile supported thereupon.

19. In combination, means presenting a support surface for a pile of sheets, means for raising or lowering said first-named means, a portable support member having a top load-supporting surface and adapted to be inserted between the pile and said support surface or to be withdrawn therefrom, and means operable to introduce a lm of air between the top load-supporting surface of said portable support member and the bottom of the pile during the insertion or withdrawal of the support member. 20. Apparatus as dened in claim 19 wherein said support member is provided with ports through which the air lilm is introduced at the top surface of the support member.

2l. In combination, means presenting a supporting surface for a pile of sheets, means for raising or lowering said lirst named means, a pallet adapted to be inserted between a depleted pile and said supporting surface or to be withdrawn therefrom, said pallet comprising top and bottom plates the major portions of which are disposed in parallel planes and comprising spacing and stiifening means between said plates, and means for introducing a iilm of air between said pallet and said depleted pile during the insertion o1' withdrawal of the pallet.

22. Apparatus as delined in claim 2l, comprising also means for introducing a film of air between said pallet and said supporting surface, whereby insertion or withdrawal of the pallet is facilitated.

23. In combination, means comprising a supporting surface for a pile of sheets, means for raising or lowering said first named means, a pallet adapted to be inserted between a depleted pile and said supporting surface or to be withdrawn therefrom, said pallet having top and bottom plates the major portions of which are disposed in parallel planes, spacing and stiifening means between said plates, at least one of said plates having ports therethrough, and means for introducing air under pressure into said pallet and discharging it through said ports.

2'4. Apparatus as defLned in claim 23, wherein the forward edge of the pallet is wedge shaped, said wedge shaped edge having a series of open ports spaced therealong.

25. In va machine of the character described, lifting bars adapted to be inserted beneath a loaded skid, means for raising said lifting bars and a loaded skid carried thereby, a pallet adapted to be inserted between said skid and a depleted pile carried thereon, means for forcing air under pressure between said pallet and said depleted pile as the pallet is pushed into position beneath the pile, and means for raising the pallet gradually while a new skid-supported pile is being placed in position beneath the pallet and being raised by said lifting bars into engagement with the pallet, said means for forcing air under pressure between the pallet and the depleted pile acting also as the pallet is being withdrawn and the depleted pile deposited upon the new pile.

26. In a machine of lthe character described, front end feeding means of the type in which the level of the pile must be maintained approximately at a certain predetermined distance below sheet separating mechanism, a skid for supporting a pile of sheets, means for raising said skid gradually to maintain the top of the pile at said predetermined level, a pallet with a flat bottom plate and an upper plate with a downwardly inclined forward end, said pallet being adapted to be inserted between said skid and a depleted pile carried thereby and to support one edge of the depleted pile while maintaining it at approximately the same level as before, and means for raising the pallet gradually while a new skid-supported pile is being raised into engagement with said pallet, whereby the level of the forward edge of the depleted pile is maintained substantially constant and said feeding means is adapted to function uninterruptedly.

27. ln a machine of the character described, front end feeding means of the type in which a certain spacing no greater than a predetermined maximum amount must be maintained between two elements, namely the sheet separating means and the pile of sheets, a skid for supporting the pile of sheets, means for moving one of said elements toward the other gradually to maintain said predetermined spacing substantially constant as sheets are fed from the top of the pile, a pallet with a downwardly inclined forward end portion providing a front edge of a thickness less than said maximum spacing, said pallet being adapted to be inserted from the rear between said skid and a depleted pile carried thereby and to support the forward edge of the pile at approximately the same level as before, means for supporting said pallet independently of said skid and moving it :relative to said sheet separating means while the feeding of sheets continues, said skid being then removable and replaceable with a new loaded skid, and means for bringing the top of the new pile and the bottom of said pallet into juxtaposition, whereby the pallet may be withdrawn and the depleted pile deposited upon the new pile during continuance of the sheet feeding operation.

28. In a sheet feeding means, the combination of means for supporting a pile of sheets, means operating `at one edge of the pile for separating and feeding sheets one at a time from the pile, a pallet having an edge portion of reduced thickness relative to other portions thereof adapted to be inserted beneath a depleted pile of sheets in a direction to cause its edge of reduced thickness to be disposed beneath said separating and feeding means, and means for supporting said pallet and the depleted pile thereon during operation of the separating and feeding means.

29. A relatively thin, portable device for insertion into or withdrawal from a pile of sheets, comprising substantially smooth top and bottom plates, ports in at least one of said plates, and means for conducting air under pressure through said device and between said plates to said ports during insertion or withdrawal of the device for facilitating movement of the device relative to the pile.

30. In a machine of the character described, feeding means of the type in which the level of the pile must be maintained approximately at a certain predetermined distance below sheet separating mechanism, main supporting means for a pile of sheets, means for raising said main supporting means gradually to maintain the top of the pile at said predetermined level, a pallet adapted to be placed between said main supporting means and said pile, said pallet having substantially flat bottom and the top surface being inclined downwardly to meet the bottom surface and provide a wedge shape at the forward edge of the pallet, and auxiliary supporting means engaging said pallet after the pile has been substantially depleted by the feeding of sheets from the top thereof, s-aid auxiliary supporting means supporting said pile while said main supporting means is lowered to receive a new pile of sheets and is again raised to present the top of the new pile adjacent to the bottom of said pallet, said pallet being adapted to be withdrawn from between said depleted and said new piles whereby said wedge-shaped forward edge gradually and evenly deposits said depleted pile upon said new pile during withdrawal.

31. Mechanism as defined in claim 30 wherein said main pile supporting mechanism and said sheet separating mechanism move relatively toward each. other during withdrawal of the pallet from between the depleted and new piles.

32. A portable pallet for insertion between or withdrawal from a pack of sheets and a supporting surface therefor, said pallet comprising a relatively thin and stiff body portion having a generally llat upper surface of area larger than the area of the sheets of said pack, the thickness of said body portion being small as compared to the larger dimension of said surface to provide a platelike member, said pallet being capable of supporting the pack of sheets independently of the supporting surface, and means connected to said body portion at a point outside the area of said pack when the pack is supported thereon for introducing a film of air between said upper surface and said pack yduring the insertion or withdrawal of the pallet.

33. A pallet according to claim 32, wherein said pallet has an air chamber below said flat upper surface and connected to said air introducing means, and ports in said upper surface through which air from said chamber passes to provide said film of air.

34. A pallet according to claim 33 including a plurality of valves in the fiat upper surface, said valves each having an operating portion protruding above said fiat upper surface and adapted to be progressively operated by the pack of sheets during relative movement of the pack of sheets and pallet.

35. A portable device of the character described comprising structure defining a top load-supporting surface and a bottom surface opposed thereto and spaced therefrom, said surfaces approaching each other closely along corresponding edges of the surfaces to provide a thin edge portion for the device of generally V-shaped cross section for leading the device between a pile of sheets and a support therefor, a plurality of ports in said edge portion and in and distributed along at least one of said surfaces, and means for conducting air under pressure through said device and between said surfaces to said ports.

36. A portable device as defined in claim 35 wherein said structure is a hollow structure which defines an air chamber and said means for conducting air under pressure through said device includes said air chamber.

37. A portable device as defined in claim 35 wherein said device is a pallet comprising a top platelike member providing said load-supporting surface and a bottom platelike member providing said bottom surface, and said top platelike member has a portion inclined downwardly to meet said bottom platelike member to provide said edge of generally V-shaped cross section, said bottom platelike member lying substantially in a single plane.

38. In the method as defined in claim 12 wherein a plurality of portable support means are inserted individually between the pile and pile support to provide the second support for the pile.

39. A methodV of handling a pile of sheets comprising the steps of inserting support means between the pile and its supporting surface, supplying air between the support means and the sheet of the pile adjacent to the support means during the insertion of the support means, and utilizing the support means to handle the pile of sheets independently of said supporting surface.

40. A method as defined in claim 39 wherein the air is introduced between the support means and the adjacent sheet of the pile by supplying the air from within the support means.

41. A method as defined in claim 40 wherein a plurality of portable support 4means are individually inserted between the pile and its supporting surface and are used as a support to handle the pile independently of the supporting surface.

42. In a portable load-supporting device comprising structure dening a member adapted to be inserted bctween a pile of sheets and a supporting surface therefor, said member having a top load-supporting surface and a bottom surface opposed thereto and spaced therefrom, a plurality of ports in and distributed along said load-supporting surface, and means for conducting air through said device to said ports.

43. ln combination, first sheet supporting means for supporting a pile of sheets, raising and lowering means for said first sheet supporting means, second sheet supporting means adapted to be moved generally parallel to the plane of the sheets of said pile for insertion therebeneath and above said first sheet supporting means, means operable to introduce air under pressure against the underside of the sheet of said pile next to said second sheet supporting means during insertion of said second sheet supporting means to facilitate said insertion, and further means for supporting said second sheet supporting means when in pile supporting position and operable to raise said second sheet supporting means.

44. in combination, the structure as defined in claim 43 wherein said second sheet supporting means comprises a plurality of members individually insertable beneath the pile on said first sheet supporting means to define a support which is supported and raised by said further means.

45. in combination, first means presenting a supporting surface for a pile of sheets, raising and lowering means for said first means, portable sheet support means adapted to be inserted above said surface and under a pile of sheets on said surface, said portable means including portions extending beyond opposite sides of a pile when in pile supporting position, air supply means operable to introduce air under pressure against the underside of the sheet of 4said pile of sheets which is next to said portable means during insertion of said portable means to facilitate said insertion, and further means for engaging said extending portions of said portable means to support the latter when in pile supporting position.

46. In combination, the structure as defined in claim 45 wherein said portable sheet support means comprises a plurality of members each having a top load-supporting surface and ports in said load-supporting surface, said air supply means comprising said ports and means for conducting air under pressure through said members to said ports.

References Cited in the file of this patent UNITED STATES PATENTS 1,488,673 Henderson Apr. 1, 1924 1,498,966 Henderson June 24, 1924 1,945,248 Winkler et al Ian. 30, 1934 2,156,139 Backhouse Apr. 25, 1939 2,170,422 Novick Aug. 22, 1939 2,214,896 Baker Sept. 17, 1940 2,549,364 Bobst Apr. 17, 1951 2,817,521 Koch Dec. 24, 1957 

